The invention concerns an airfoil sail for a sailboat consisting of a mast with several sail crossbeams superposed one above the other to be raised or reefed on the mast and between each of which is an external sail covering spanning the maximum vertical spacing, the crossbeams comprising at least two horizontal sections connected to one another by a vertical hinge shaft and jointly corresponding to a symmetrical airfoil, and one of the sections encloses the mast.